Character display discharge tube

ABSTRACT

A character display discharge tube of low power consumption type comprising an insulating base board having an arrangement of a number of discharge elements organized into groups each constituting a basic character form, an insulating mask plate stacked on said insulating base board and having many holes individually leaving the respective discharge elements uncovered, and a transparent window plate supporting a phosphor film and stacked on said insulating mask plate. In this discharge tube, the discharge elements in each group are selectively driven for discharge to excite corresponding portions of the phosphor film with the resultant electromagnetic radiation, thereby obtaining a glow display of a character on the film surface.

United States Patent Kunii 1 Mar. 18, 1975 CHARACTER DISPLAY DISCHARGE TUBE [76] Inventor: Takao Kunii, 10-9 Mukonaso-l-chome, Amagasaki, Japan [22] Filed: July 17, 1973 [21] Appl. No.: 380,098

[30] Foreign Application Priority Data July 20, 1972 Japan 47-73206 Aug. 25, 1972 Japan 47-85613 [52] US. Cl. 313/514, 3l3/5.l7, 315/169 TV [51] Int. Cl. HOlj 7/42 [58] Field of Search 313/108, 109.5, 210, 220, 313/513, 514, 515, 516, 520, 517; 315/169 TV, 169 R [56] References Cited UNITED STATES PATENTS 3,237,040 2/1966 Kupsky 313/1095 3,260,880 7/1966 Kupsky.... 313/210 3,281,619 10/1966 Greene 313/109.5

3,346,759 10/1967 Hardwick 313/109.5

3,384,770 5/1968 Vodicka 313/109.5 3,406,288 10/1968 Du Bois 313/109.5 3,504,214 3/1970 Lake 313/109.5

3,619,694 11/1971 Tanji 313/108 3,668,466 6/1972 Shimada.... 315/169 TV 3,723,789 3/1973 Tanji 313/108 R Primary ExaminerJames W. Lawrence Assistant Examiner-D. C. Nelms Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher [57] ABSTRACT A character display discharge tube of low power consumption type comprising an insulating base board having an arrangement of a number of discharge elements organized into groups each constituting a basic character form, an insulating mask plate stacked on said insulating base board and having many holes individually leaving the respective discharge elements uncovered, and a transparent window plate supporting a phosphor film and stacked on said insulating mask plate. In this discharge tube, the discharge elements in each group are selectively driven for discharge to excite corresponding portions of the phosphor film with the resultant electromagnetic radiation, thereby obtaining a glow display of a character on the film surface.

8 Claims, 6 Drawing Figures PATENTED 1 8 I975 SHEET 1 0r 3 PATENTE R 1 8 ms I sum 2 o 3 38726346 FIG.2

CHARACTER DISPLAY DISCHARGE TUBE This invention relates to improvements in display systems and, more particularly, to character display discharge tubes of a low power cunsumption type.

As the prior-art character display discharge tube of this type, there is a glow discharge type character display tube disclosed in US. Pat. No. 3,041,491 issued on June 26, 1962, and particularly shown in FIG. 6 thereof.

Such prior-art discharge tube has certain drawbacks. Firstly, it cannot be operated with low power since a phosphor film is interposed between paired discharge electrodes. Secondly, it is difficult to obtain a clear contour of the glow display. Thirdly, it has been difficult to obtain a multi-digit character display since this leads to complications of the electrode structure for selectively energizing discharge elements.

An object of the invention is to overcome the drawbacks inherent in the prior art and provide a novel character display discharge tube which can be operated with low power.

Another object of the invention is to provide a character display discharge tube, whose glow display section has a simple construction with a simple selective energization electrode structure and is capable of multidigit character display.

A further object of the invention is to provide a character display discharge tube, which is capable of clear glow display of characters with comparatively small cathode area and with very low power.

According to the invention, there is provided a character display discharge tube comprising an insulating base board having an arrangement of a number of discharge elements organized into groups each constituting a basic character form, an insulating mask plate stacked on said insulating base board and having many holes individually leaving the respective discharge elements uncovered, and a transparent window plate supporting a phosphor film and stacked on said insulating mask plate.

The above and other objects, features and advantages of the invention will become more apparent from the following detailed description of preferred embodiments of the invention when taken in conjunction with the accompanying drawings, in which:

FIGS. la, 1b, and 1c is a fragmentary exploded perspective view showing essential parts of an embodiment of the character display discharge tube according to the invention;

FIG. 2 is a fragmentary plan view of the essential part of the discharge tube of FIG. 1;

FIG. 3 is a fragmentary perspective view'of the character display discharge tube of FIG. 1; and

FIG. 4 is a view similar to FIG. 2 but showing a different embodiment of the. character display discharge tube according to the invention.

An embodiment of the character display discharge tube will now be described with reference to the accompanying drawing. Referring to FIG. 1, reference numeral 4 designates an insulating base board consisting of a stack of thin insulating plates 1, 2 and 3 of such material as glass or ceramic. It is provided on its top surface with many cathodes and anodes individually associating with and provided near respective cathodes. These cathodes and anodes constitute discharge elements organized into groups each for each digit. In the illustrated example, each discharge element group consists of 7 discharge elements. For example, a first digit is constituted by a set of cathodes k to k, and anodes a, to a The cathodes are led through busbars extending between the plates 1 and 2 to one edge of the board, and anodes are led through busbars extending between the plates 2 and 3 to another edge of the board. For example, the seven anodes a, to a, inthe first discharge element group are connected to a common terminal A and the seven cathodes k, to k, in this group are connected to respective terminals K, to K In the second discharge element group, the anodes a to a are connected to their common terminal A and the cathodes k to k are connected commonly with the corresponding cathodes k, to k, in the first group to the respective terminals K, to K An insulating mask plate 5 made of mica or like material is stacked on the insulating board 4. It has many elongate holes H, to H H toH etc., organized in groups for the individual digits such that, for instance, the hole H is locatedat the position of the discharge element consisting of cathode k, and'anode a the hole H is located at the position of the discharge element consisting of cathode k and anode a and the hole H is located at the position of the discharge element consisting of cathode k and anode a FIG. 2 shows the base board 4 and mask plate 5 in the assembled state.

A transparent window plate 6 consisting of a flat glass plate and having a phosphor film 7 uniformly provided on its underside is stacked on the insulating mask plate 5. Edge portions of the window plate 6 are sealed to the insulating base board 4 by means of frit glass 8 such that these parts form a gas-tight envelope. The interior of the envelope is evacuated through a thin tube 9 integrally formed with the insulating base board 4, and thereafter a discharge medium consisting of helium or a gas mixture of helium and neon, a gas mixture of helium and argon or a gas mixture of helium, neon and argon or mixture of such gases and mercury vapor is sealed in the envelope through the thin tube 9.

The holes formed in the insulating mask plate 5 thus define respective small discharge spaces. These small discharge spaces and the thin tube 9 communicate with one another through a slight gap between the base board 4 and mask plate 5, but they are isolated with re spect to the discharge phenomenon by the mask. plate 5.

Such flat discharge tube may be driven by a wellknown time-division drive circuit such as one disclosed in FIG. 4 of the US. Pat. No. 3,641,383. When a discharge element is activated, the electromagnetic wave generated in the associated small discharge space excites a phosphor film portion in contact with this space, and the glowing can be seen through the transparent window plate 6.

While in the preceding embodiment each discharge element has been constituted by a cathode and an anode, it is also possible to form each discharge element with three electrodes, namely cathode, control grid and anode. FIG. 4 shows an example of the latter construction. In the Figure, seven control grids g to g, for the first digit are connected to their common terminal 6,. Likewise, seven control grids 3, to g for the second digit are connected to their common terminal G in this construction, all the anodes a to (1 a to a are led to a single common terminal A. In this case, an anode voltage of, for instance to volts is selectively applied between one or more of the terminals K, to K and the terminal A, and a bias voltage lower than the anode voltage, for instance 120 to 150 volts, is applied to the terminals (3,, G In this state, the discharge elements for the individual digits will not glow but are held in a glow-ready state. By subsequently applying a pulse voltage of about 25 volts in superimposition upon the bias voltage to, for instance, terminal G the glowing of the surface of the selected cathodes of the second digit is produced, so that the electromagnetic wave generated in the associated small discharge spaces excites phosphor film portions in contact with these spaces, and the glowing can be seen through the transparent window plate.

While the preceding embodiments have used seven discharge elements and seven holes for each digit, it is possible to use -a different number of discharge elements and associated holes arranged in a different basic form for each digit. Also, the discharge elements and leads leading from them may be formed by means of deposition, etching or other suitable means. Further, they can be formed in any suitable form such as dots and stripes 1 As has been made apparent from the foregoing, with the character display discharge tube according to the invention a number of discharge elements in a set can be selectively driven for exciting phosphor film portions in contact with the corresponding small discharge spaced with the generatd electromagnetic radiation. Thus, it is possible to obtain sufficiently clear glow display of characters with comparatively small cathode area and with very small power. Also, it is possible to make arrangements such as to be able to select the color of the glow. Further, the invention particularly lends itself to applications to a multi-digit tube for multi-digit character displays.

What we claim is:

l. A character display discharge tube comprising an insulating base board; a multiplicity of discharge elements each including a cathode and an anode in proximate relation and arranged in groups on said base board, each of the groups constituting a basic character form; a flat insulating plate stacked on said insulating base board, said plate being formed with a plurality of apertures for the passage of radiation from the cathode and anode of the respective discharge elements; a transparent viewing plate stacked on said insulating mask plate; and a phosphor film applied to the inside of said transparent viewing plate and spaced from the cathodes and anodes of said discharge elements through said apertures in said mask plate, said phosphor generating light when activated by radiation, said base board, said apertures and said transparent plate constituting an envelope containing a gas atmosphere.

2. The character display discharge tube according to claim 1, wherein the basic character formed by each group of discharge elements represents the numeral 8.

3. The character display discharge tube according to claim 1, wherein a control grid is interposed between said cathode and said anode.

4. A character display discharge device comprising a. an insulating base board formed of first, second and third stacked insulating plates,

b. a multiplicity of pairs of spaced first and second electrodes arranged on said first insulating plate,

0. a first conductive bus bar interposed between two adjacent stacked insulating plates, said bus bar being connected to the first electrodes in said pairs of electrodes,

d. a multiplicity of second conductive bus bars interposed between the other two adjacent stacked insulating plates, each of said second bus bars being connected to a corresponding second electrode in each of said pairs of electrodes,

e. a flat insulating mask stacked on said insulating base board and having a multiplicity of apertures, each of said apertures exposing one of said pair of electrodes,

f. a transparent viewing plate secured to said insulating base board overlying said flat insulating mask and spaced from said pairs of electrodes,

g. a phosphor film secured to the surface of said viewing plate facing said insulating mask, and

h. a gaseous discharge medium contained within the envelope formed by said transparent viewing plate and said insulating base board, each pair of electrodes generating electromagnetic waves when a voltage is impressed therebetween thereby exciting said phosphor film causing it to emit light in the vicinity of said pair of electrodes.

5. A character display discharge device as defined by claim 4 wherein said multiplicity of second conductive bus bars are parallel to each other and perpendicular to said first conductive bus bar. 1

6. A character display discharge device as defined by claim 4 wherein said first electrodes connected to said first bus bar are anodes and said second electrodes each connected to one of said second bus bars are cathodes.

7. A character display discharge device as defined by claim 6 wherein a control grid is interposed between the first and second electrodes of each pair of electrodes.

8. A character display discharge device as defined by claim 4 wherein said gaseous discharge medium in- 

1. A character display discharge tube comprising an insulating base board; a multiplicity of discharge elements each including a cathode and an anode in proximate relation and arranged in groups on said base board, each of the groups constituting a basic character form; a flat insulating plate stacked on said insulating base board, said plate being formed with a plurality of apertures for the passage of radiation from the cathode and anode of the respective discharge elements; a transparent viewing plate stacked on said insulating mask plate; and a phosphor film applied to the inside of said transparent viewing plate and spaced from the cathodes and anodes of said discharge elements through said apertures in said mask plate, said phosphor generating light when activated by radiation, said base board, said apertures and said transparent plate constituting an envelope containing a gas atmosphere.
 2. The character display discharge tube according to claim 1, wherein the basic character formed by each group of discharge elements represents the numeral
 8. 3. The character display discharge tube according to claim 1, wherein a control grid is interposed between said cathode and said anode.
 4. A character display discharge device comprising a. an insulAting base board formed of first, second and third stacked insulating plates, b. a multiplicity of pairs of spaced first and second electrodes arranged on said first insulating plate, c. a first conductive bus bar interposed between two adjacent stacked insulating plates, said bus bar being connected to the first electrodes in said pairs of electrodes, d. a multiplicity of second conductive bus bars interposed between the other two adjacent stacked insulating plates, each of said second bus bars being connected to a corresponding second electrode in each of said pairs of electrodes, e. a flat insulating mask stacked on said insulating base board and having a multiplicity of apertures, each of said apertures exposing one of said pair of electrodes, f. a transparent viewing plate secured to said insulating base board overlying said flat insulating mask and spaced from said pairs of electrodes, g. a phosphor film secured to the surface of said viewing plate facing said insulating mask, and h. a gaseous discharge medium contained within the envelope formed by said transparent viewing plate and said insulating base board, each pair of electrodes generating electromagnetic waves when a voltage is impressed therebetween thereby exciting said phosphor film causing it to emit light in the vicinity of said pair of electrodes.
 5. A character display discharge device as defined by claim 4 wherein said multiplicity of second conductive bus bars are parallel to each other and perpendicular to said first conductive bus bar.
 6. A character display discharge device as defined by claim 4 wherein said first electrodes connected to said first bus bar are anodes and said second electrodes each connected to one of said second bus bars are cathodes.
 7. A character display discharge device as defined by claim 6 wherein a control grid is interposed between the first and second electrodes of each pair of electrodes.
 8. A character display discharge device as defined by claim 4 wherein said gaseous discharge medium includes helium. 